ABSTRACT Prostate cancer (PC) is the second leading cause of cancer-related deaths in the United States. Although it is regarded as a highly treatable disease if detected early, therapeutic options for patients with recurrence following hormonal therapies are extremely limited. While many types of nano-delivery systems with different materials and physiochemical properties have been pursued over the years, effective strategies to block tumor progression and prevent metastasis are still lacking. Thus, there is an urgent need to develop a new treatment regime for patients suffering from prostate cancer. In recent years, RNA interference (RNAi) approaches using small interfering RNA (siRNA) and micro RNAs (miRNA) have been shown to down-regulate specific gene expression in cancerous cells or cells infected with virus. However, the therapeutic value of RNAi has been hindered by the lack of an efficient, pathogen-free delivery system to target specific cells. We have recently developed a panel of highly stable, non-immunotoxic and reconfigurable nucleic acid nanoparticles (NANPs) for therapeutic delivery purposes to overcome the most frequently encountered RNAi challenges that include specific targeting, stability, and co-delivery of multiple therapeutics to target different genes or multiple sites on one gene. This library of the NANPs has multiple advantages such as stable in blood serum (resistant to enzymes), non-immunoresponsive (advantageous for repeated systemic delivery), and prolonged shelf-life at ambient conditions (convenient to store and transport). The goal of this proposal is to conjugate our NANPs with PC specific targeting RNA aptamer and therapeutic molecules siRNA and miRNA and screen the resulting therapeutic nanoparticles for the top candidate(s) to be tested in animal models. For targeted delivery into the PC cells, aptamers targeting to PC-3 and LNCaP cells such as XEO2 will be incorporated. The siRNA targeting several anti-apoptosis factors and miRNA that can up-regulate the expression of the tumor suppressor genes will be used as main therapeutic agents. This proposal aims to demonstrate the feasibility of applying novel nano-scaffolds to treat prostate cancer (used as an example) and to investigate efficacy of size, shape and number of therapeutic payloads per nanoparticle. Significantly reduced total cost of production will make it possible to study all the constructs proposed in the current R03 application. Our major expectation is that this study will serve as a proof-of- concept demonstrating the advantage of the NANPs for enhanced and synergistic therapeutic of diseased cells. The results will serve as a justification that reconfigurable property of NANPs can be conjugated with other user defined cell targeting and therapeutic modules.